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Wyszukujesz frazę "Balaz, P." wg kryterium: Autor


Wyświetlanie 1-3 z 3
Tytuł:
Photocatalytic Properties of Mechanochemically Synthesized Nanocrystalline $ZnAl_2O_4$ and CdSe
Autorzy:
Kostova, N.
Eliyas, Al.
Fabián, M.
Achimovičová, M.
Baláž, P.
Powiązania:
https://bibliotekanauki.pl/articles/1375494.pdf
Data publikacji:
2014-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.-n
61.05.cp
61.46.-w
61.66.Fn
Opis:
Nanocrystalline powders of $ZnAl_2O_4$ and CdSe were prepared via mechanochemical synthesis. Powder slurries were coated as thin films on $SiO_2$ thin layer chromatography (TLC) sheet by capillary method. The photocatalytic activity of the film coating was tested in a self-made gas-phase flat-plate continuous-flow photocatalytic reactor with toluene as model air contaminant. The tested nanocrystalline $ZnAl_2O_4$ turned out to be poor oxidation photocatalyst under UV irradiation. CdSe displays considerable photocatalytic activity under visible light, where $TiO_2$ is inactive. The nonconventional one-step mechanochemical route to $ZnAl_2O_4$ and CdSe synthesis offers several advantages compared to traditional processing routes, including low-temperature solid state reactions at ambient temperature, absence of organic templates contamination and low expenses.
Źródło:
Acta Physica Polonica A; 2014, 126, 4; 967-970
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of Mechanochemically Synthesized Mixed Oxides
Autorzy:
Kostova, N.
Zorkovská, A.
Kováč, J.
Velinov, N.
Baláž, P.
Powiązania:
https://bibliotekanauki.pl/articles/1372521.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
77.84.Bw
75.60.-d
76.80.+y
61.05.cp
81.07.Wx
Opis:
The mixed oxides $Fe_{2}O_{3}-ZnO$ have been obtained in nanocrystalline state by reactive milling in a high-energy planetary mill, from a stoichiometric mixture of hematite and ZnO. The magnetic properties of samples were evaluated by magnetization measurements and Mössbauer spectrometry. A post milling annealing promotes the solid state reaction and improves the zinc ferrite formation, paramagnetic $ZnFe_{2}O_{4}$ phase is formed. Further mechanical activation leads to structural transformation into Wüstite-type (FeZn)O mixed oxide, with ferromagnetic hysteresis and increased magnetization.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 411-412
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties and Sorption Activity of Mechanically Activated Magnetite $Fe_3O_4$
Autorzy:
Baláž, P.
Timko, M.
Kováč, J.
Bujňáková, Z.
Ďurišin, J.
Myndyk, M.
Šepelák, V.
Powiązania:
https://bibliotekanauki.pl/articles/1535173.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.60.Ej
61.05.cp
76.80.+y
Opis:
It is known that the action of mechanical forces on solids (mechanical activation and/or mechanochemistry) leads to changes of their properties and reactivity. We have studied the physico-chemical and sorption properties of magnetite $Fe_3O_4$ (Kiruna, Sweden) mechanically activated in a planetary mill. Several methods such as X-ray diffractometry, Mössbauer spectroscopy, magnetometry, specific surface area measurement as well as arsenic sorption tests have been applied. By X-ray diffractometry strong amorphisation of magnetite has been evidenced. In parallel, specific surface area increased from 0.1 $m^2//g$ for the reference (non-milled) sample to the values 0.5-6.1 $m^2//g$ for milled samples. The Mössbauer spectrum of the reference sample is well fitted with two subspectra corresponding to tetrahedrally (A) and octahedrally (B) coordinated iron cations in the spinel structure of $Fe_3O_4$. In mechanically activated samples (B)-site subspectrum becomes asymmetric, while (A)-site spectrum remains more or less unchanged. The more covalent character of the Fe(A)-O bond compared to the Fe(B)-O bond can explain qualitatively why the spin-density transfer from (A) to (B) in the spinel structure is more effective than vice versa. The value of the saturation magnetization at room temperature was 67.4 ≈ 43.6 emu/g which is significantly lower than that of the bulk particles 92 emu/g. This reduction may be attributed to the surface disorder or spin canting at the particle surface. During the milling process the coercivity value increases from 150 Oe up to 460 Oe with milling time. This increase can be related to the fact that magnetic anisotropy may increase when particle size decreases. The sorption activity of $Fe_3O_4$ was enhanced as a consequence of its disordering: 88% of $As^{3+}$ was captured for the mechanically activated sample in comparison with 0% for the non-milled one.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 1005-1007
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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